IE59997B1 - Rotating piston machine. - Google Patents

Description

The invention relates to a rotating piston machine with a housing, with a shaft mounted in the housing, with an annular space, in which two rotating bodies are located and against whose walls, in which inlet and outlet openings are provided for the working medium, the rotating bodies form a sealing fit, each rotating body having four sector-shaped vanes which extend radially outwards, the two rotating bodies being coaxially arranged and their vanes meshing in such a way that at any one time of one rotating body is engaged between two vanes of the other rotating body, a cam path control being provided by means of which, when the shaft rotates, both rotating bodies rotate with cyclic variations in. the rotating speed and the distances between the vanes of the two rotating bodies, the cam path control having internal cam rings which have a torsionally resistant mounting on the shaft.

Various rotating piston machines are known, all of which, however, possess different disadvantages. Particularly frequent is the problem of balance, with the result that the known rotating piston machines often run very untrue, thereby giving rise firstly to shuddering and noise and secondly to very severe loading of the bearings.

A known rotating piston machine of the type referx'ed to initially (GB-PS 299,775) exhibits various disadvantages. Simple geometrical considerations demonstrate that in this case the guidance of the rolling elements between the internal cam path and the external rolls cannot be free of play. This is not possible, whatever the geometry of the internal cam path. The transmission of power via the differently seated rolls is very small, so that only a low efficiency can be attained which bears no relation to the masses in motion. In the load-change area, that is to say, the reversal points of the cam path, there is no reciprocal action; these are dead points. The seating of the rolls is not described and is clearly unresolved. Because of the problems mentioned, it is likely that a rotating piston machine corresponding to the reference would, to say the least, run very unevenly and have low efficiency.

The aim is to create a rotating piston machine of very high efficiency which is basically free from problems due to uneven running.

In the solution according to the invention the cam path control has external east rings with a torsionally resistant mounting on & rotating body and rolling elements which are able to move radially but are held stationary in the peripheral direction by a cage connected to the housing, in each case four of the rolling elements roll between one internal cam ring and one external cam ring and for each rotating body equipped with such a cam path control two pairs of internal/external cam rings are provided, each with four rolling elements.

The cam path control according to the invention enables th® two rotating bodies to be set in motion in such a way that, as they rotate, the volume of the working spaces on both sides of them is varied cyclically in conjunction with inlet and outlet openings, so that the desired mode of operation is attained.

Power transmission takes place over the shortest rout© via two cam path surfaces in each case. The flow of power is ensured at every point on the cam path. Furthermore, operation, is free of play. The cam geometry can be so devised that uniform acceleration values are attained, so enabling the acceleration torque to be reduced.

For each rotating body, eight frictional-contact rolling elements operate free from play. Power transmission takes place both by th® lifting action of the rolling elements and by traction between the cam paths and the rolling elements (i.e. the rolling of the rolling elements on the cam paths.) The rotating piston machine can be used as a compressor, e.g. for gases. On the other hand, it can also be used as an engine if the compressed gases are conveyed into a separate combustion chamber, blended with fuel and ignited, after which the gases are reintroduced into the annular working space so as to drive the rotating body.

As the shaft turns and with it the internal cam ring on its torsionally resistant mounting, this cam ring, if the turning motion moves its rolling surface radially outwards relatively to the rolling element, thrusts the rolling element outwards. This indirectly causes the outer cam ring to turn, as it must give way in such a manner that the rolling element finds a position in which the roll-way on the outer cam ring is situated radially further out. In this way the rotary movement is transmitted from the shaft to the outer cam ring and so to the rotating body. The speed and the way it changes are determined by the shape of the curved paths on the cam rings. When the rolling elements have reached the outermost position, they can transmit no further torque from the inner ring to the outer cam ring. The movement is thereupon continued by the second set of inner/outsr cam rings until th© first set of inner/outer cam rings is again able to transmit torques.

It would admittedly be conceivable to provide only one of the rotating bodies with the aforementioned cam path control and to fasten, the other directly to the shaft. Eo«evarf this solution is less attractive, as the rotating piston machine is then no longer able to run evenly. It is therefore expedient to provide a cam path control for each rotating body.

If cylindrical rolling elements are chosen, changes in distances and therefore circumferential lengths of the cam paths on the cam rings mean that the rolling elements cannot roll properly but to some extent have to slide, thereby causing frictional losses.

It is therefore expedient to give the rolling elements a conical taper on both sides and to ensure that in the radial and axial directions the cam rings provide roll-ways conforming to a specified function.

By applying this technique and a suitable choice of functions it is possible to ensure that the rolling elements roll evenly and without friction and do not slide on the roll-ways of the inner and outer cam ring. The axial function for the roll-way is derived from the radial function. It is necessary to make sure that, for a given rotation of the rolling element through a specified angle, the rolling element on both roll-ways rolls without sliding. This is achieved by changing the effective diameter of the rolling element, the track being axially shifted to a point where the effective diameter of the rolling element has the appropriate value owing to its conicity.

It is expedient to make the rolling elements and the cam rings mirror-symmetrical relative to a radial plane of the shaft. Th© result is that the rolling elements then always lie against two mirror-symmetrical parts of a double roll-way and cannot skew.

If the cam rings comprise two mirror-symmetrical halves, they are especially simple to manufacture. Both cam. ring halves (including the roll-way configuration) then basically assume the shape of truncated cones, so that the outer ring-halves, in particular, are easier to manufacture. In addition, this simplifies the assembly of the whole device.

If the cam rings can be clamped in the axial direction by providing a gap between the cam ring halves, axial loading can be used to press the cam ring halves firmly against the rolling elements, so that the whole assembly is free of play. This axial loading can be beneficially applied by spring action.

As already mentioned, tow pairs of cam rings have to be provided for each rotating body. If one set of cam rings of the pair is identical with but oppositely mounted to the other set of cam rings of the pair and If th© rolling elements of one set of cam rings are displaced by 45° relative to the set of the other cam rings, the two sets of rolling elements can then be mounted fairly close to each other in the axial direction, so reducing the total size. Balancing Is also better under these conditions. If the same cam rings are used for both sets, the number of different cam rings also becomes very small. Only two outer cam ring halves and two inner cam ring halves have to be produced. Th® fact that the second set of cam rings is oppositely mounted, that is to say, that th® circumferential function acts in a way precisely opposite to that of the other set, enables the transmission of power to take place continuously, so that at any time when one set is not transmitting power this function is assumed by the other set.

If, beneficially, the vanes of the rotating bodies have in a plane containing the shaft axis the shape of a square, one diagonal of which is perpendicular to the shaft axis, and if the housing comprises two halves whose separating line is the central plane of the annular space, then the annular space is particularly easy fo manufacture and the machine can be assembled very simply. If a flexible seal is mounted between the two halves of th® housing and a clamp is provided, improved sealing action can be achieved by clamping the halves of the housing more tightly together, as the angular housing halves then rest very firmly against th® surfaces of the rotating bodies lying at 45° to the shaft.

Furthermore, if provision is mad© for changing the angular positioning of the cages relative to the housing, the position of the inlet and outlet openings can also be altered. Although th® relative cyclic motion of the two rotating bodies remains identical, the rotating bodies, or the working spaces contained between them, then imping® on the inlet and outlet openings at different times, so that the mode of operation of the machine can hs altered by a simple means.

In an advantageous form of the machine at least parts of the external radial wall are made up of hollow, mobile elements fitted with seals which, when the contact pressure on the vanes decreases with a consequent deterioration in the sealing action, are again pressed more firmly against the vanes by a. leakage current which arises under these conditions. This provides a very simple and effective means of automatically regulating the sealing action between the rotating bodies and the walls of the compression chamber.

It is expedient to secure the rolling elements in the cages by bearing shells or guide shoes, which ar© attached to th® cages by toothing systems in such a way that they ere able to rotate in one direction but are prevented from moving in a direction perpendicular to this.

In many cases the input power, when the rotating piston machine is being used as a compressor, or the output power, when the rotating piston machine is being used as an engine, will he transmitted through the shaft. However, the two rotating bodies or parts connected to them can also be rigidly connected to the rotor of a motor/generator whose stator is connected to the housing. In this advantageous form of the machine the drive, when the rotating piston machine is being used as a compressor, acts not on th® shaft but directly on the two rotating bodies. In this case the speed of the drive, especially where a disc-rotor type motor is used, can be very effectively adapted to changes in the speed of rotation of the rotating bodies. The shaft then, has to transmit no more than the action of balancing or adjusting the speeds of rotation of the two rotating bodies positively controlled by the rolling elements and the cam paths. The situation is similar when the rotating piston machine is used as an engine? in this case the rotors of disc-rotor generators are rigidly connected to the rotating bodies.

By the provision in accordance with the invention of eight rolling elements, free of play, for each rotating body, the rotating bodies are effectively seated. Apart from the previously mentioned advantage of smooth running and high efficiency, this also means that additional bearings for the rotating bodies can be completely dispensed with.

The invention is described below by the example of some advantageous forms of the machine illustrated In the attached drawings. These are as follows; Figure 1 Section through a radial plane of the annular space with the two rotating bodies; Figure 2 The two rotating bodies in different positions; Figure 3 The cam path control principle in accordance with the invention; Figure 4 Section in an axial plane of the shaft traversing inner cam ring, rolling element and external cam ring; Figure 5 View of rolling element and cage components, seen radially from outside; Figure 6 Side view of inner cam ring; Figure 7 Flan view of cam ring in Figure 6; Figure 8 Sectional view of outer cam ring; Figure 9 Plan view of cam ring in Figure 8; Figure 10 Axial view of cage details and rolling element guiding system; Figure 11 Section through the machine in accordance with the invention; Figure 12 Axial section through the annular working space in another embodiment of the invention; and Figure 13 View similar to Figure 11 of another embodiment of the invention.

Figure 1 shows the annular space 1 enclosed by parts of the housing 2. In the annular space 1 are located the two meshing rotating bodies designed as vane wheels 3 and 4. Vane wheel 3 has vanes 3a, 3b, 3c and 3d, while vane wheel 4 has vanes 4a, 4b, 4c and 4d. Th® two vane wheels are driven by a central shaft 5 in a manner described later. 6a - 6h are various inlet and outlet openings in the front face of the annular space 1.

This assembly operates as follows. If shaft 5 moves anticlockwise, vane wheels 3 and 4 are driven clockwise at differing speeds in a manner to be described later. In the position shown, for instance, vane wheel 4 would rotate clockwise faster than vane wheel 3. In this case, the working space between the vanes 3d and 4a would increase, so causing gas to be sucked In through inlet duct Sa. At a later stage this inlet duct Sa is closed by the slowly following vane 3d. From about this moment onwards vane 3d starts to move more quickly than vane 4a, so that th® working space between the two vanes is reduced and the gas Is compressed until the two vanes have advanced sufficiently for the working space to arrive above opening 6b, where the gas is able to escape. At this point vane 3d can be brought right up to vane 4a so that the gas is completely expelled.

This mode of operation can be used both for a compressor and for an internal combustion engine. Only combustion chambers, fuel lines, etc. would have to be provided.

Figure 2 illustrates four phases of the working cycle described above. After the two rotating bodies have turned through 90°, a new working cycle begins.

Figure 3 illustrates the principle of the cam path control In accordance with the invention. The radial sections in Figure 3 show on the Inside an internal cam ring 7 with a torsionally resistant mounting on shaft 5 and surrounded on the outside by an outer cam ring 8 connected to one of the rotating bodies 3,4. Between the inner and outer cam rings there are rolling elements 9 at 90° intervals. A cage secures these in relation to the housing 2 in such a way that they can move only radially outwards or inwards but cannot move in the direction of rotation of the shaft or of the inner and outer cam rings 7,8.

If the inner cam ring 7 turns anticlockwise, as is illustrated by the transition from the left-hand image to the central image in Figure 3, its outer profile presses the rolling elements 9 outwards. This causes the outer cam ring 8 to rotate clockwise, as it has to move in this direction to make room for the rolling elements 9. When th® central position has been attained, a corresponding movement hy another set consisting of inner cam ring, rolling elements and outer cam ring causes the turning motion to proceed until the position to the right of Figure 3 is attained, which corresponds to that of th© starting position on the left. In this way the rotation of the shaft 5 is converted into a turning movement of the rotating bodies 3,4 in the annular space, this turning movement being, however, non-uniform and determined by the curve geometry of the inner and outer cam rings 7,8.

If the rolling elements 9 were cylindrical, they could not roll uniformly on the inner and outer cam ring 7,8 but would tend rather to slide, as the path curvatures are different. This can b® overcome by the rolling elements 9 in accordance with the invention, which have a double-conical shape, as shown in section in Figure 4 . It is apparent that the rolling element 9 has various effective rolling diameters. For instance, on the left 10 is a mean rolling diameter for rolling on the outer cam ring 8, while 11 on the right is a mean rolling diameter for rolling on the inner cam ring 7. Reference is made here to mean ' diameters, as the area of contact between cam ring and rolling element is not, of course, a mathematical line but has a certain width.

As is shown in the Figure, the cam rings 7 and 8 are not made in one piece but comprise two cam ring halves 7a and 7b, 8a and 8b, which are mirror-symmetrical. Only in the area of th© roll-way 7c and 8c is the rolling element 9 in contact with these cam ring halves.

The rolling elements are held in a cage which must be visualized in Figure 4 in front of and behind th© rotating element 9. A plan view of this cage, or part of it, is shown in Figure 5» The rolling element 9 is held by two bearing shells 12 in which the rolling element is able to rotate in sliding contact. On the outside, the bearing shells have teeth which engage a corresponding rack 13 ox the cage 14. This signifies that the rolling element 9 in Figure 5 is able to move forward or to the rear, i.e. radially in relation to th© rotating piston machine, or up or down in Figure 4» However, it is prevented from making an angular movement relative to the housing, i.e. from moving to the right or left in the presentation in Figure 5.

Figure S is a side view of an inner cam ring half 7a. Figure 7 is a plan view of the same cam ring half 7a. This shows the basically oblique profile of the outer surface in the form of a truncated cone with the raised roll-way 7c for the rolling elexnent 9 .

As is apparent from Figures 6 and 7, the roll-way 7c conforms in both the radial and axial directions to a function corresponding to the desired cam path control system.

Similarly, Figures 8 and 9 are a section through an external cam half ring 8a (Figure 8) and a plan view of same (Figure 9). Here again the raised roll-way 8c is apparent.

Figure 10 is again an axial view, partly sectionalised, showing the seating of the rolling elements 9 In th© cage 14 in further detail. The cam rings with the roll-ways ar© also shown.

Figure 11 is an axial section showing half the machine according to the invention. Ths other half of th© machine is essentially a mirror-symmetrical continuation to the left.

The drive shaft 5, with spacer sleeve 15, radial and axial bearings 16,17 and housing flange 18, is abl® to rotate in the housing 2. Outside the spacer sleeve 15 there is a coupling flange 19 and a nut 20. Inside th® spacer sleeve 15 there are the two, inner cam ring pairs forming inner cam rings 7. To the right there is a spacer sleeve 21 leading to the corresponding inner cams 7 on the other side, which are used to drive the other one of the two rotating bodies.

Via the spacer sleeves 15 and 21 and a corresponding thrust element on the unshown left-hand side of th© machine, the two halves of the inner cam rings 7 are pressed together by tightening the nut 20 so that the rolling elements 9 are pressed outwards against the outer cam rings 8. These also consist of two halves with a torsionally-resistant mounting in a jacket 22 connected to the rotating body 3 . Locking flanges 23 do not merely secure th© outer cam rings 8 but press them together so as to generate a counter-pressure to the pressure of the rolling elements S. Springs can also be used to press together the halves of the inner cam rings 7 or outer cam rings 8.

Finally, the cage 14 In which the rolling elements 9 are held is fastened to the housing flange 18 and is rendered torsionresistant by a rack-tooth cage mounting 24 on the other side of the assembly. This anchors the cage relative to th© housing in the circumferential direction. Th© angular setting of the cage 14 relative to the housing 2 can, however, be adjusted by altering th© angular position of the housing flange 18 in relation to the housing 2 hy means of an adjustable seating 25.

References 26-30 indicate seals, and 31 is a further seal between the halves of the housing. Finally, 32 is a bearing bush between the cage 14 and the rotor 3.

As mentioned previously, the housing 2 consists of two halves whose line of separation 33 is provided with the seal 31. If the sealing action between the vanes of the rotating bodies 3, 4 and the well of the annular space 1 deteriorates, it is possible by tightening a bolt through hoi© 34 to bring the two housing halves more tightly together, so improving the contact In th© annular space between the housing walls and th® rotating bodies 3,4 and with it the sealing action.

In the form of the machine shown in Figure 12, the vanes (not visible in Figure 12) of the rotating bodies 3 and 4 are not directly in contact with the wall of the housing 2 but with a flexible wall element 35 which acts as a seal. If this wall element 35 yields, a gap 36 opens up In the seal between the rotating body 3 and the wall element 35, or a corresponding gap occurs between rotating body 4 and a corresponding element 37 matching wall element 35» Pressurized gas now enters the gap 36 (and does likewise on the other side) and Is able to flow through an opening 38 Into the void behind wall element 35, pressing this in the direction of the arrows 39 Inwards against the vanes of the rotating body. By this means automatic regulation of th© sealing action is achieved.

In th® form of the machine shown in Fig. 13, the rotors 42 of motors or generators 40 are directly connected to the rotating bodies 3,4 Pig. 13 shows that the rotor 42 of the motor/generator Is rigidly connected via the casing 22 to the rotating body 3» Th® same applies to a second, unshown motor/generator 40 which is rigidly connected to rotating body 4. The stator 41 of these motors/generators is rigidly connected to the housing 2. In this form of the machine, the input/output power no longer passes through the shaft 5. Instead, the rotating bodies 3,4 are driven directly by the motors 40, or alternatively the rotating bodies 3,4 directly drive the generators 40, th® shaft 5 now transmitting the positively controlled co-ordination of the movements of the rotating bodies 3 and 4.

Claims (8)

1. Rotating piston machine with a housing (2), with a shaft (5) mounted in the housing (2), with an annular space (1), in which two rotating bodies (3,4) are located and against whose walls, in which inlet and outlet openings (6a-6h) are provided for the working medium, the rotating bodies (3,4) form a sealing fit, each rotating body (3,4) having four sector-shaped vanes (3a-3d and 4a-4d) which extend radially outwards, the two rotating bodies (3,4) being coaxially arranged and their vanes meshing in such a way that at any time one vane of one rotating body is engaged between two vanes of the other rotating body, a cam path control (7,8,9) being provided by means of which, when the shaft (5) rotates, both rotating bodies (3,4) rotate with cyclic variations In the rotating speed and the distances between the vanes of the two rotating bodies, the cam path control having internal cam rings (7) which have a torsionally resistant mounting on the shaft (5), characterized by the fact that the cam path control has external cam rings (8) with a torsionally resistant mounting on a rotating body (3,4) and rolling elements (9) which are able to move radially but are held stationary in the peripheral direction by a cage (3.4) connected to the housing (2), by the fact that in each case four of the rolling elements (9) roll between one internal cam ring (7) and one external cam ring (8), and by th® fact that for each rotating body (3,4) equipped with such a cam path control two pairs of intemal/extemal cam rings (7,8) are provided, each with four rolling elements (9).

2. Rotating piston machine In accordance with Claim 1 characterized by the fact that a cam path control (7, 8, 9) is provided for each rotating body (3,4)»

3. ·, Rotating piston machine in accordance with Claim 1 or 2 characterized by the fact that the rolling elements (9) are tapered on both sides and by the fact that in the radial and axial direction the cam rings (7,8) have roll5 ways (7c,8c) intended for a specific purpose.

4. Rotating piston machine in accordance with Claim 3 characterised by the fact that the rolling elements (9) and the cam rings (7,8) display mirror symmetry relative to a radial plane of the shaft (5). 10 5. Rotating piston machine in accordance with Claim 4 characterised by the fact that the cam rings (7,8) are constructed of two mirror-symmetrical halves (7a,/b; 8a,8b). β. Rotating piston machine in accordance with Claim 5 15 characterised by the fact that the cam rings (7,8) can be clamped in the axial direction. 7. Rotating piston machine in accordance with Claim 6 characterised by the fact that the cam rings (7,8) are spring-loaded in the axial direction. 20 8. Rotating piston machine in accordance with any of the Claims 1 to 7 characterized by the fact that one set of cam rings (7,8) of the pair are identical with but oppositely mounted to the other cam rings (7,8) of the pair and that the rolling elements (9) of one set of cam 25 rings (7,8) are displaced by 45° relative to those of the other cam rings (7,8). 9. Rotating piston machine in accordance with any of the Claims 1 to 8 characterised by the fact that the vanes (3a-3d, 4a~4d) of the rotating bodies (3,4) have in a 30 plane containing the shaft axis the cross-sectional shape of a square, one diagonal of which is perpendicular to the shaft axis, and by the fact that the housing (2) comprises two halves whose separating line (33) is the central plane of the annular space (1).

5. 10. .Rotating piston machine in accordance with any of the Claims 1 to 9 characterised by the fact that the angular positioning of the cages (14) relative to the housing (2) can be changed. t 11. Rotating piston machine in accordance with any of the

6. 10 Claims 1 to 10 characterised by the fact that at least ’parts of the radial outer wall of the annular space (1) consist of moveable, hollow elements (35) fitted with seals, which, when the bearing pressure against the vanes diminishes with a consequent deterioration of the sealing 15 action, are once again pressed more firmly against the vanes by a leakage flow which this situation causes.

7. 12. Rotating piston machine in accordance with any of the Claims 1 to 11 characterized by the fact that the rolling elements (9) in the cages (14) are held by bearing shells 20 or guide shoes (12) with toothed attachments (13) to the cage (14) such that they can perform a rolling motion in one direction.

8. 13. A rotating piston machine substantially as hereinbefore described with reference to the accompanying drawings.